KR20030068340A - Method and Apparatus for Treating N-containing Wastewater Using Granular Zeolites - Google Patents

Abstract

PURPOSE: Provided are a method and an apparatus for treating nitrogen-containing wastewater at low cost with great treatment efficiency by using a sequencing batch biofilm reactor and granular zeolite as microorganism media. CONSTITUTION: The method comprises a first anoxic or anaerobic step for denitrifying wastewater and removing ammonium nitrogen contained in the wastewater by ion exchange of zeolite filled in a reactor; an aerobic step for detaching the ammonium nitrogen from the zeolite by exposing the zeolite to nitrifying bacteria under the aerobic condition; and a second anoxic or anaerobic step for removing nitrate generated during the aerobic step. The apparatus includes a reactor(111) filled with zeolite, a raw water inlet pipe(121) connected to the reactor(111) for introducing wastewater to the reactor(111) therethrough, a water level sensor(171) installed at an upper portion of the reactor(111) for controlling flow of the wastewater, a treated water discharging pipe(123) connected to the reactor(111) for discharging clean water which is treated in the reactor(111) therethrough, and an air pump(161) installed at a lower portion of the reactor(111) for supplying air to the zeolite after discharging the treated water, thereby detaching ammonium nitrogen adsorbed to the zeolite by nitrification.

Description

Method and apparatus for treating nitrogen-containing wastewater using granular zeolite {Method and Apparatus for Treating N-containing Wastewater Using Granular Zeolites}

The present invention is a technique related to sewage and wastewater treatment using a continuous batch biofilm reactor using a granular zeolite as a carrier, particularly a technique related to nitrogen removal. The present invention relates to a process of continuously removing organic matter, nitrogen and phosphorus from sewage and wastewater by forming a biofilm after filling a granular zeolite in a reaction tank and injecting wastewater into the wastewater. The conditions are changed from anaerobic or anoxic state to aerobic state through an air supply in a single reaction tank serving as a carrier to reduce organic matter by using ion exchange properties of ammonia nitrogen of zeolites and biofilms and microorganisms attached to zeolites. Alternatively, the present invention relates to a method for economically increasing the removal efficiency of organic matter, nitrogen, phosphorus, suspended solids (ss), etc. in sewage and wastewater as denitrification occurs in anoxic state and nitrification in aerobic state.

Most of the existing sewage and wastewater treatment plants are using activated sludge method, but this process is mainly for the removal of organic matter, and it is the process of nitrogen and phosphorus, which are known to cause eutrophication of lakes and cattle, which are serious social problems recently. It is not suitable as a removal process. Efforts have been made in developed countries to replace the activated sludge process, such as an A / O method with one anaerobic tank and one aerobic tank, one anaerobic tank, one anaerobic tank, and one aerobic tank. A ² / O method, which is a method of arranging, the Bardenpho method, the improved UCT method, the continuous batch (SBR) method to give an oxygen-free, aerobic state treatment in a single reactor, And the biofilm method using a carrier. However, in these processes, the removal efficiency of the wastewater treatment containing high concentration of nitrogen depends on the return cost, the demand of land is high, the settling deterioration due to the breeding of filamentous bacteria in activated sludge, or the stable operation of the reactor. It implies.

In general, in order to remove nitrogen biologically, ammonia nitrogen present in sewage and wastewater has to be converted to nitrate nitrogen by nitrifying bacteria under aerobic conditions, and the converted nitrate nitrogen is the action of denitrification bacteria under anaerobic or anoxic conditions. Is reduced to nitrogen molecules and removed. In order for this process to proceed smoothly, ammonia must be converted into nitrate nitrogen form by nitrification in an aerobic tank, and denitrification must be performed smoothly in an anaerobic or anoxic tank. However, despite the fact that nitrogen and phosphorus affecting the eutrophication of lakes and cattle should be almost completely treated in the treatment plant, the high concentration of nitrogen-containing wastewater such as leather wastewater, livestock wastewater, and leachate water, Due to the action of inhibiting activity and insufficient amount of organic matter compared to ammonia concentration, the existing activated sludge process does not perform nitrification itself well. As a result, it is difficult to remove nitrogen, thus increasing the environmental pollution of the ecosystem. .

On the other hand, research results for biological wastewater treatment of sewage and wastewater by applying the natural zeolite selectivity to ammonia (e.g. Korean Patent No .: 0282212, 00275004, 0273856, 0188878, 0188804) Has been reported. However, these methods reduce the concentration of ammonia nitrogen by using a series of methods such as relying on the ion exchange capacity of the zeolite to ammonia nitrogen to induce an improvement in adsorption and nitrification. When saturated, the present invention relates to a method of using a substance such as sodium chloride for regeneration of zeolite, or by transporting microorganisms in a biological treatment tank to promote the regeneration. However, when this method is used, an additional zeolite ion exchange device is required, and a cost burden due to artificial regeneration of the ammonia-adsorbed zeolite, loss due to occurrence of blockage in the zeolite reactor, and the like are expected. On the other hand, Japanese Patent Application Laid-Open No. 10-99893 uses a regeneration method using biological mechanisms for the powdered zeolite administered in the treatment tank. However, this method requires separate reaction tanks for anaerobic or anoxic tanks, aerobic tanks, and settling tanks. The sludge control problem may occur due to the growth method, and it is difficult to separate only the zeolite due to the characteristics of the powdered zeolite, and the problem of having to replenish the lost zeolite due to the disposal of excess sludge is to recycle the sludge and the zeolite decomposed through the ozone treatment. Although the method was proposed, it did not mention the possibility that the phosphorus concentration of the effluent could be increased in this case, and there was an economic problem as a separate ozone treatment device was needed. In addition, it is not technically easy to apply the proposed method in the treatment of high concentration organic sewage and wastewater. In addition, Japanese Patent Application Laid-Open No. 2000-325987, which applies a similar principle, suggests a method for regenerating zeolites which have been desorbed with ammonia by placing a separate zeolite packed layer, but the zeolite is simply used in a basic process in the order of an anoxic tank, an aerobic tank and a settling tank. The apparatus is complicated by providing a biological regeneration method by attaching the packed bed to the rear stage, and the problem of efficiency of the device occurs because the zeolite filling tank is used only as an ion exchange device of residual ammonia nitrogen.

Currently, the regulation of nitrogen in the world is being tightened, so water nitrogen is causing many environmental problems in Korea. Therefore, despite the fact that a wastewater and wastewater treatment process that can efficiently and effectively remove nitrogen is required, most of the nitrogen removal processes do not overcome the drawbacks depending on the return cost or are to be solved by installing additional reactors.

Accordingly, the present invention is to improve the above-mentioned conventional technical problems, ammonia nitrogen in a single reactor in the use of a granular zeolite having an ion exchange capacity with respect to ammonia nitrogen based on the biofilm process as a carrier Ion exchange, denitrification, nitrification (biological regeneration), and filtration reactions are all carried out without the sludge decomposition process such as supplementation of additional zeolite or ozonation for reuse of powdered zeolite. The present invention relates to a method and apparatus that can be used semi-permanently through operation and at the same time eliminate the problem of deterioration of sedimentation or time for precipitation, and can drastically increase nitrogen removal efficiency and removal efficiency of suspended solids. As well as leather, animal husbandry and saliva That in high concentration nitrogen wastewater containing a number of such cost-effective and can be applied effectively, and intended to provide a biofilm sequencing batch processing method and apparatus using the granular zeolite as a carrier in the waste water treatment.

1 is a schematic diagram of a continuous batch biofilm reactor for sewage and wastewater treatment,

2 is an example of the operating cycle of a continuous batch biofilm reactor.

<Description of main parts of drawing>

111: reactor

121: raw water inlet pipe

122: internal return pipe

123: treated water outflow pipe

124: backwash water outflow pipe

125: backwash water inlet pipe

131: raw water inflow pump

132: internal conveying pump

133: backwash water inflow pump

141: solenoid valve for treatment water discharge

142: solenoid valve for backwash water discharge

151 zeolite carrier

161: air pump

162: air pump for backwash air supply

163: diffuser

171: water level sensor

172: DO (Dissolved Oxygen) or ORP (Redox potential) measuring sensor (DO or ORP sensor)

173 pH sensor

181: auto controller

In order to achieve the above object, the present invention provides a method for treating wastewater containing nitrogen, wherein the influent containing organic matter and nitrogen in a single reactor is denitrified by denitrification bacteria under anaerobic or anaerobic conditions and is present in the influent. The anoxic or anaerobic step of removing the ammonia nitrogen by the ion exchange of the zeolite packed in the reaction tank, the zeolite adsorbed by the ammonia nitrogen through the anoxic or anaerobic step is brought into contact with the nitrifier under aerobic conditions in the reaction tank, Zeolite comprising the step of desorbing ammonia nitrogen from the zeolite through the process of nitrifying the nitrogen, characterized in that to remove the nitrate nitrogen generated through the aerobic step with the organic matter through anoxic or anaerobic step again. Nitrogen containing It relates to a method of treating wastewater.

In addition, in order to achieve the above technical problem, in the present invention, a zeolite-filled reaction tank, a raw water inlet pipe connected to the reaction tank to introduce wastewater and wastewater, a water level control sensor to control the flow rate of the inflow water, and anoxic in the reactor Or a treated water outlet tube which denitrifies under anaerobic conditions and discharges the treated water from which the ammonia nitrogen is removed by the zeolite, and is placed under the reactor to supply air to the zeolite to form aerobic conditions and adsorb the ammonia to the zeolite. Provided is a treatment apparatus for nitrogen-containing sewage and wastewater using zeolite, comprising an air pump for nitrifying and desorbing nitrogen.

On the other hand, after the exhalation step by supplying air to the zeolite filled in the reaction tank may further include a backwashing step to remove the microorganisms attached to the zeolite and overgrown.

The method further comprises the step of introducing the raw water into the single reactor prior to the anaerobic or anaerobic step, and further comprising the step of exiting the reactor prior to the exhalation step.

In addition, the method, characterized in that it further comprises a step of removing the residual organic matter to form aerobic conditions prior to the outflow step to remove the residual organic matter.

The backwashing step may be characterized in that the washing water is supplied to the zeolite in addition to the air to remove the microorganisms that are overgrown by being attached to the zeolite.

The washing water may be discharged through the backwash water outlet pipe attached to the reaction tank through the backwash water outlet pipe attached to the reaction tank, and then separated into solid and liquid through the precipitation or filtration process.

On the other hand, the inflow water introduced into the reactor is conveyed internally in the upward or downward direction for smooth contact between the microorganisms or floating microorganisms attached to the zeolite and the substrate in the wastewater.

In addition, the zeolite is characterized in that the natural zeolite or a synthetic zeolite having an ion exchange capacity for ammonia nitrogen.

The present invention includes an automatic control device for automatically controlling the operation of the device.

In addition, the zeolite is preferably filled in an amount within the range of 20% to 100% of the effective volume of the reaction tank to maintain an environment suitable for attaching the microorganisms and an environment suitable for maintaining the microorganisms at an appropriate level, the diameter is 0.1 It is possible to use those in the range of mm to 100 mm, preferably those in the range of 3 mm to 10 mm.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention. In the apparatus of FIG. 1, the granular zeolite 151 is filled in a range of 20 to 100% of the volume of the reactor in a circular or rectangular reactor 111 made of a structure or a material such as plastic or stainless steel. The pump includes a raw water inflow pump 131, an internal conveying pump 132, a backwash water inflow pump 133, and an air pump 161, an air pump 162 for supplying back air, and an diffuser 163. And, the automatic switch 141 for treatment water discharge and the automatic switch 142 for backwash water discharge are installed in the reaction tank. The flow pipe for the movement of the main fluid (waste water) includes a raw water inlet pipe 121 for raw water injection, an inner return pipe 122 for return water, a backwash water inlet pipe 125 for backwash water injection, and treatment water drainage. It consists of a treated water outlet pipe 123 and a backwash water outlet pipe 124 for drainage of backwash water. In addition, the sewage and wastewater treatment system by the water level control sensor 171, DO or ORP measuring sensor 172, pH measuring sensor 173 and the automatic control device 181 to automatically control the operation of the reactor for adjusting the influent flow rate. This is the final composition. Looking at the operation and its operation with respect to the configuration of the present invention are as follows. Operation is performed as shown in FIG.

The raw water of the wastewater and wastewater is introduced for a predetermined time through the raw water inflow pipe 121 by the operation of the raw water inflow pump 131 to the reaction tank configured as shown in FIG. This is called an inflow step (2a in FIG. 2).

The inflow is stopped by the contact with the water level control sensor 171, the conveying pump 132 is operated so that the fluid is continuously circulated in the reaction tank through the inner conveying pipe (122). This is called the anaerobic or anaerobic stage (2b in FIG. 2). In this state, air is not injected to maintain anoxic state.

When the reaction in the anaerobic or anoxic stage is maintained for a predetermined time and then finished, the automatic switchgear 141 for treating water discharge is automatically opened and the fluid (treated water) in the reaction tank is discharged to the level where the outlet pipe is located. This process is called an outflow step (2c in Fig. 2). If necessary, the aerobic state may be maintained for a certain period of time for the purpose of removing organic matter that has not been completely consumed prior to the outflow step.

After the outflow process, the air pump 161 and the internal transfer pump 132 for air injection are operated at the same time. This process is called aerobic or nitrification step (2d in FIG. 2).

During the anaerobic and anaerobic (nitrification) reactions, microorganisms are attached to the zeolite carrier and grow continuously. The microorganisms that are overgrown are properly removed to prevent blockage or short circuit in the reactor. A backwashing process is needed. This is called a backwashing step (2e in Fig. 2).

After the backwashing process, the raw water inflow pump 131 is operated again, and the inflow stage (2a of FIG. 2) is started again. DO or ORP measuring sensor 172 and pH meter 173 for monitoring the dissolved oxygen and pH state in the reactor while the reactor is operating continuously.

These series of processes are controlled by the automatic control device 181, and the sewage and wastewater treatment is performed while circulating and repeating the process of FIG.

In the anaerobic or anaerobic stage, denitrification is carried out using a carbon source (COD or BOD) existing in the introduced raw water containing nitric acid nitrate, which has been nitrated by a zeolite carrier or suspended nitrifying bacteria in the fluid in the reactor. The denitrification reaction occurs by the oxidizing bacteria, and the organic matter in the fluid is removed, and the nitrate nitrogen is reduced and removed to the atmosphere in a gaseous state (N ₂ ). At the same time, ammonia nitrogen in the introduced raw water is exchanged through the ion exchange to the zeolite. Rearranging this process, the organic matter in the influent or externally supplemented carbon sources (methanol, acetic acid, etc.) and nitrate nitrogen are removed through biological denitrification by denitrification bacteria attached or suspended on the zeolite surface. Ammonia nitrogen in the influent is a principle that is removed by chemical ion exchange in the zeolite carrier.

In the aerobic or nitrification step, the ammonia nitrogen ion-exchanged in the zeolite is gradually desorbed into the fluid of the reactor through the biological nitrification reaction and is released. At the same time, the ion exchange is carried out by cations (Na ⁺ etc.) contained in the fluid. Biological regeneration of the carrier takes place. This means that the zeolite carrier is restored to its original state through biological regeneration, which has the ability to ion exchange ammonia nitrogen again. On the other hand, when the pH falls below a certain value through the nitrification reaction in the process of aerobic (2d in Figure 2), the activity of the microorganisms is reduced, so the alkalinity should be supplemented as necessary. Generally, drugs such as NaOH or NaHCO ₃ Used.

The backwash phase is not necessarily included in every cycle. For example, a backwashing step may be included in each cycle, and in some cases, once every two to three or more cycles. When the backwashing process is completed after the reaction for a predetermined time in the aerobic state (2d of FIG. 2), the backwash air supply air pump 162 is about 2 to 5 times more than the air flow rate of the air pump 161 to maintain the aerobic state. It runs for a certain amount of time. Thereafter, the automatic switchgear 142 for backwash water discharge is opened, and the fluid is discharged to the automatic switchgear level together with the microorganisms detached from the carrier. If necessary, backwash water for washing microorganisms detached from the carrier is used as wash water by the backwash water inflow pump 133. The discharged fluid is solid-liquid separated through a process such as precipitation or filtration, and the fluid from which solids including microorganisms are removed is introduced again into the reactor through the backwash water inflow pump 133. Through this process, the microorganisms grown by overgrowth on the carrier are properly removed from the zeolite and phosphorus is removed through the removal of the microorganisms.

<Example>

Hereinafter, the Example of this invention is described. However, the following examples are only preferred embodiments of the present invention to aid in understanding of the present invention, and the contents of the present invention are not limited to the following examples.

The empirical experiment was conducted by the configuration of the present invention (FIG. 1), operation and operation (FIG. 2). The reactor 111 is made of acrylic material and manufactured in an effective volume of 3 L. The zeolite 151 used is a granule having a diameter of 2.5 to 4.5 mm as a natural zeolite of Kowloonpoic acid clinoptilolite series produced in Korea. Type zeolite was charged into the reactor in a volume of 1 L (fill rate: 33%).

Comparative Example

For comparative experiments, granular activated carbon (Samchully) having the same diameter and little ion exchange capacity was filled in the same sized reactor in the same volume.

Influent water was artificially prepared in the laboratory, and the chemical oxygen demand (CODcr) was 900 mg / L, ammonia nitrogen was 200 mg / L, phosphorus was 9 mg / L, and alkalinity was 1000 mg / L. As the operating conditions, the influent flow rate was 0.7L, the hydraulic retention time (HRT) was operated at 4.3 days based on the effective volume of the reactor, and a series of processes (see FIG. 2) were performed for 24 hours (hr). It was made. Specifically, the inlet time was 30 minutes, the anaerobic reaction time was 8 hours, the outflow time was 5 minutes, and the aerobic (or nitrification) reaction time was 15 hours and 25 minutes. The backwash was performed once a week for 10 minutes. On the other hand, in the case of DO anaerobic or anaerobic stage was less than 0.2mg / L, at the aerobic stage was maintained at more than 4mg / L, the pH was maintained overall 7 or more.

The results of Examples and Comparative Examples are shown in [Table 1]. The results of Table 1 show high removal efficiencies for organic matter, nitrogen and phosphorus in the case of the embodiment of the present invention, and in particular, nitrogen showed more than about 95% total nitrogen removal efficiencies. 20 to 25% lower than that.

Analysis item Influent Example Comparative example Chemical oxygen demand Concentration (mg / L) 900 20-50 30 to 60 Removal efficiency (%) - 94.4 to 99.8 93.3 to 96.7 Ammonia nitrogen Concentration (mg / L) 200 2 to 10 40-60 Removal efficiency (%) - 95.0 to 99.9 70.0-80.0 Total nitrogen Concentration (mg / L) 200 2.5 to 11.5 41 to 61.5 Removal efficiency (%) - 94.3 to 99.8 69.3-79.5 A total person Concentration (mg / L) 9 2 to 5 2.5 to 6 Removal efficiency (%) - 44.4 ~ 77.8 33.3 to 72.2

The sewage and wastewater treatment method and apparatus of a continuous batch biofilm reactor using a granular zeolite according to the present invention as a carrier is characterized in that the sewage and wastewater treatment rate is increased by using a carrier capable of fixing a large number of microorganisms compared to the floating growth method. It is 2 to 5 times faster than the process, can be used semi-permanently through biological regeneration, maximizes the removal of nitrogen, and because all processes are performed in a single reactor, no additional equipment is required, which saves money. It requires less land area, simple operation and operation, and economical effect.

Claims (16)

In the method of treating sewage and wastewater containing nitrogen, Oxygen-free or anaerobic step of denitrifying influent containing organics and nitrogen in a single reactor with denitrification bacteria under anoxic or anaerobic conditions, and removing ammonia nitrogen present in the influent by ion exchange by zeolite packed in the reactor. ; And The aerobic step of desorbing ammonia nitrogen from the zeolite through the process of nitrifying the ammonia nitrogen by contacting the zeolite to which the ammonia nitrogen adsorbed through the anoxic or anaerobic step in the reaction tank under aerobic conditions to nitrify the ammonia nitrogen Include, The method for treating nitrogen-containing sewage and wastewater using zeolite, characterized in that the nitrate nitrogen generated through the aerobic step is removed together with the organic matter through the anoxic or anaerobic step. The method of claim 1, After the exhalation step, further comprising a backwashing step of removing the microorganisms attached to the zeolite by the air supply to the packed zeolite in the reaction tank to remove the overgrown, nitrogen-containing sewage and wastewater Treatment method. The method of claim 2, The method further comprises the step of introducing raw water into the single reactor prior to the anaerobic or anaerobic step, and further comprising the step of effluent of the treated water from the reactor prior to the aerobic (nitrification) step. Method of treating nitrogen-containing sewage and wastewater using The method of claim 3, The method further comprises a step of removing residual organic matter by forming an aerobic condition prior to the outflow step to remove residual organic matter, the method for treating nitrogen-containing sewage and wastewater using zeolite. The method according to any one of claims 2 to 4, In the backwashing step, in addition to the air, washing water is supplied to the zeolite in the reaction tank to remove microorganisms attached to the zeolite and overgrown. The method of claim 5, The washing water is the treatment of nitrogen-containing sewage and wastewater using zeolite, characterized in that the backwash water generated through the backwashing step is discharged from the reaction tank and separated into solid and liquid through the precipitation or filtration process and then introduced into the reaction tank again. Way. The method of claim 1, The inflow water introduced into the reaction tank is internally conveyed in an upward or downward direction for smooth contact between the microorganisms or the floating microorganisms attached to the zeolite and the substrate in the wastewater. . The method for treating nitrogen-containing sewage and wastewater using zeolite according to any one of claims 1 to 7, wherein the zeolite is a natural zeolite or a synthetic zeolite having ion exchange ability with respect to ammonia nitrogen. In the wastewater and wastewater treatment apparatus containing organic matter and nitrogen, A reactor filled with zeolite; A raw water inlet pipe connected to the reactor to introduce the waste water into the reactor; A water level control sensor positioned at an upper portion of the reactor to adjust a flow rate of the inflow water; A treated water outlet pipe which is denitrified under anoxic or anaerobic conditions in the reactor and discharges treated water from which ammonia nitrogen has been removed by the zeolite; And Located in the lower portion of the reactor and after the treated water is discharged through the treated water outlet pipe to supply air to the zeolite to create an aerobic condition, by nitrifying the ammonia nitrogen adsorbed to the zeolite and includes an air pump An apparatus for treating sewage and wastewater containing nitrogen using a zeolite, characterized in that The apparatus for treating sewage and wastewater according to claim 9, A nitrogen-containing sewage and wastewater treatment apparatus using zeolite, further comprising an air pump for supplying backwash air to supply air to the zeolite in order to remove the microorganisms grown on the zeolite. The apparatus for treating sewage and wastewater according to claim 10, A nitrogen-containing sewage and wastewater treatment apparatus using zeolite, further comprising a backwash water outlet pipe for discharging backwash water containing microorganisms detached from the zeolite by the backwash air supply air pump from the reaction tank. The apparatus for treating sewage and wastewater according to claim 11, Nitrogen-containing sewage and wastewater treatment apparatus using zeolite, characterized in that it further comprises a backwash water inlet pipe for separating the backwash water discharged through the backwash water outlet pipe through solid-liquid separation through sedimentation or filtration and then introducing it back into the reactor. . The apparatus for treating sewage and wastewater according to claim 9, The nitrogen-containing sewage and wastewater treatment apparatus using zeolite which further includes the inner conveying pipe which discharges inflow water in the said reaction tank, and returns it to a reaction tank again. The method according to any one of claims 8 to 13, The sewage and wastewater treatment apparatus, A nitrogen-containing sewage and wastewater treatment device using zeolite, further comprising an automatic control device for automatically controlling the operation of the device. 10. The nitrogen-containing sewage and wastewater treatment apparatus using zeolite according to claim 9, wherein the packed zeolite is filled in an amount within a range of 20% to 100% of the effective volume of the reactor. 10. The nitrogen-containing sewage and wastewater treatment apparatus using zeolite according to claim 9, wherein the filled zeolite has a diameter in the range of 0.1 mm to 100 mm.